Nutrient concentrations in coastal waters: Impact of the Guadiana River

Nutrient concentrations in coastal waters: Impact of the Guadiana River

 Water samples were collected over an area of 900 km2 adjacent to the outflow of the Guadiana River in January 1999 to characterize the concentrations and spatial distribution of nutrients (ammonium, nitrite, nitrate, phosphate and silicate) in the water column. The purpose of the study was...

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Autores principales: Cravo, A, Madureira, M, Rita, F, Silva, AJ, Bebianno, MJ
Formato: Online
Lenguaje:eng
Publicado: Iniversidad Autónoma de Baja California 2003
Acceso en línea:https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/167
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id oai:cienciasmarinas.com.mx:article-167
record_format ojs
institution Ciencias Marinas
collection OJS
language eng
format Online
author Cravo, A
Madureira, M
Rita, F
Silva, AJ
Bebianno, MJ
spellingShingle Cravo, A
Madureira, M
Rita, F
Silva, AJ
Bebianno, MJ
Nutrient concentrations in coastal waters: Impact of the Guadiana River
author_facet Cravo, A
Madureira, M
Rita, F
Silva, AJ
Bebianno, MJ
author_sort Cravo, A
title Nutrient concentrations in coastal waters: Impact of the Guadiana River
title_short Nutrient concentrations in coastal waters: Impact of the Guadiana River
title_full Nutrient concentrations in coastal waters: Impact of the Guadiana River
title_fullStr Nutrient concentrations in coastal waters: Impact of the Guadiana River
title_full_unstemmed Nutrient concentrations in coastal waters: Impact of the Guadiana River
title_sort nutrient concentrations in coastal waters: impact of the guadiana river
description  Water samples were collected over an area of 900 km2 adjacent to the outflow of the Guadiana River in January 1999 to characterize the concentrations and spatial distribution of nutrients (ammonium, nitrite, nitrate, phosphate and silicate) in the water column. The purpose of the study was to characterize a winter situation of low discharge in terms of nutrient concentrations in the coastal area adjacent to the Guadiana outflow, before the reduction of the river flow due to the completion of the Alqueva Dam. The results show that the maximum influence of the Guadiana outflow was close to the mouth of the Guadiana River, where the highest nutrient concentrations and the minimum of salinity were registered. At the surface, the nutrient concentrations decreased gradually as the distance from the coast increased. The influence of the Guadiana outflow at the surface, despite being small, was evident in the area of about 90 km2 that extends westwards from the mouth of the river. In this area, the increase in N compounds was more significant than in P and Si. The vertical influence of the outflow of the Guadiana River, until over the isobath lower than 30 m, was reflected in nutrient concentrations that decreased with the increase in depth. However, when the depth of the water column was greater than 30 m, the nutrient concentrations increased with the increase in depth. It is expected that with the completion of the Alqueva Dam, the outflow of the Guadiana River will be reduced even further. Nutrient concentrations will also be reduced and the influence of the river in the coastal zone will be even smaller. This could have a negative impact on the nutrient biogeochemical cycles and on the overall productivity of the area.
publisher Iniversidad Autónoma de Baja California
publishDate 2003
url https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/167
_version_ 1715723938236989440
spelling oai:cienciasmarinas.com.mx:article-1672019-04-24T21:29:39Z Nutrient concentrations in coastal waters: Impact of the Guadiana River Concentraciones de nutrientes en aguas costeras: Impacto del Río Guadiana Cravo, A Madureira, M Rita, F Silva, AJ Bebianno, MJ nutrients Guadiana River coastal waters Alqueva Dam nutrientes Río Guadiana aguas costeras Presa Alqueva  Water samples were collected over an area of 900 km2 adjacent to the outflow of the Guadiana River in January 1999 to characterize the concentrations and spatial distribution of nutrients (ammonium, nitrite, nitrate, phosphate and silicate) in the water column. The purpose of the study was to characterize a winter situation of low discharge in terms of nutrient concentrations in the coastal area adjacent to the Guadiana outflow, before the reduction of the river flow due to the completion of the Alqueva Dam. The results show that the maximum influence of the Guadiana outflow was close to the mouth of the Guadiana River, where the highest nutrient concentrations and the minimum of salinity were registered. At the surface, the nutrient concentrations decreased gradually as the distance from the coast increased. The influence of the Guadiana outflow at the surface, despite being small, was evident in the area of about 90 km2 that extends westwards from the mouth of the river. In this area, the increase in N compounds was more significant than in P and Si. The vertical influence of the outflow of the Guadiana River, until over the isobath lower than 30 m, was reflected in nutrient concentrations that decreased with the increase in depth. However, when the depth of the water column was greater than 30 m, the nutrient concentrations increased with the increase in depth. It is expected that with the completion of the Alqueva Dam, the outflow of the Guadiana River will be reduced even further. Nutrient concentrations will also be reduced and the influence of the river in the coastal zone will be even smaller. This could have a negative impact on the nutrient biogeochemical cycles and on the overall productivity of the area. En un área de 900 km2 alrededor de la desembocadura del Río Guadiana se recolectaron muestras de agua para caracterizar las concentraciones y distribución espacial de nutrientes (amonio, nitritos, nitratos, fosfatos y silicatos) en la columna de agua. El propósito de este estudio fue caracterizar la condición invernal de pocas descargas, en términos de concentración de nutrientes en el área costera adyacente a la desembocadura del Guadiana, antes de que el flujo del río se vea reducido por la conclusión de la Presa Alqueva. Los resultados indican que la mayor influencia de la descarga del Guadiana se observó cerca de la boca del río, donde se registraron las mayores concentraciones de nutrientes y la salinidad más baja. En superficie, las concentraciones de nutrientes disminuyeron gradualmente con el aumento de la distancia a la costa. La influencia de la descarga del Guadiana en superficie, aunque pequeña, fue evidente en el área de ~90 km2 que se extiende de la boca del río hacia el oeste. En esta área el incremento de compuestos de N fue más significativo que el de los de P y Si. La influencia vertical de la descarga del Río Guadiana, hasta por encima de la isóbata < 30 m se reflejó en las concentraciones de nutrientes que disminuyeron conforme aumentaba la profundidad. Sin embargo, cuando la profundidad de la columna de agua era > 30 m las concentraciones de nutrientes aumentaron con la profundidad. Es de esperar que con la terminación de la Presa Alqueva la descarga del río se vea aún más disminuida. Las concentraciones también se verán reducidas y la influencia del río en la zona costera será aún menor. Esto podría tener un impacto negativo en los ciclos biogeoquímicos de nutrientes y en la productividad global del área. Iniversidad Autónoma de Baja California 2003-03-06 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Peer-reviewed Article Artículo Arbitrado application/pdf https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/167 10.7773/cm.v29i4.167 Ciencias Marinas; Vol. 29 No. 4 (2003); 483-495 Ciencias Marinas; Vol. 29 Núm. 4 (2003); 483-495 2395-9053 0185-3880 eng https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/167/143

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